Servicing Mission Observatory Verification (SMOV) Update

07.20.09

 

During Servicing Mission 4, astronauts replaced many key parts — batteries and gyroscopes, for example — that affect the spacecraft component of the Hubble Space Telescope. Testing and calibration for the spacecraft itself is now complete, and that aspect of Hubble is in excellent shape.

• Hubble is now functioning with three of its six new gyroscopes. As planned, the other three have been turned off to keep in reserve.
• Hubble's new batteries are performing as expected, with more charging capacity than the ones they replaced.
• The new thermal panels are functioning as anticipated, keeping equipment Bays 5, 7, and 8 at their expected temperatures.

Testing and calibration continues on the science components.

• The Science Instrument Command and Data Handling Unit (SIC&DH) has been turned on again after its June electronic malfunction, and is functioning normally. The problem has not reoccurred. Engineers continue to monitor the SIC&DH.
• All instruments contain a number of channels, which detect and processes different wavelengths. Wide Field Camera 3 is now aligned and focused in both of its channels, and is undergoing calibration.
• Scientists and engineers have nearly finished aligning the Cosmic Origins Spectrograph (COS). When an instrument enters space, weightlessness can cause it to go out of alignment. Engineers adjust the instrument from the ground, controlling tiny mirrors inside the instrument. One channel is fully aligned, and the other's alignment should be completed over the next few days. COS's other planned calibrations, typically involving internal measurements of the instrument, are going well. The COS far-UV channel successfully conducted its first external observation this week in preparation for the alignment process.
• The Space Telescope Imaging Spectrograph has been suspended due to a memory anomaly. Engineers are working on the problem.
• The Advanced Camera for Surveys (ACS) has completed all testing, alignment and calibration activities and is taking science observations. Two of the instrument's channels — one seeing ultraviolet light, the other visible light — are functioning very well. The third, a high-resolution channel that, for example, takes pictures of the central regions of galaxies, could not be restored during the servicing mission. This channel was thought to have a 50-50 chance of being brought back online, so the result is not unexpected. The return of the visible light channel, responsible for many of ACS's famous images, is a particular triumph.

 

 

Space Telescope Science Institute (STScI)
Baltimore, MD